Congress is rushing to strike a deal to fund large parts of the government by Dec. 7 to avoid a partial government shutdown. On Thursday, Trump said “there certainly could be” a shutdown over border security as he seeks $5 billion for wall construction in the next fiscal year.

As backlash over the use of tear gas mounts, Trump again finds himself embroiled in an immigration crisis worsened by his administration’s actions and marked by visceral images of children suffering. The tactics may only embolden Democrats as Trump tries to secure their votes for one of his top political goals.

Democrats seized on the images that started circulating Sunday. One in particular — which showed a woman grasping two bare-footed children as they run from a plume of gas spreading behind them — sparked outrage.

“Shooting tear gas at children is not who we are as Americans,” wrote Tom Perez, chairman of the Democratic National Committee, in a tweet. “Seeking asylum is not a crime. We must be better than this.”

The Trump administration defended its tactics on Sunday night. In a statement, Homeland Security Secretary Kirstjen Nielsen said “some of these migrants attempted to breach legacy fence infrastructure along the border and sought to harm [Customs and Border Protection] personnel by throwing projectiles at them.”

“As I have continually stated, DHS will not tolerate this type of lawlessness and will not hesitate to shut down ports of entry for security and public safety reasons,” she said.

The escalating border crisis once again puts Trump in the position of defending the use of controversial tactics on migrant children. Earlier this year, he justified his administration’s separation of migrant parents from children as a deterrent to illegal entry, only to rescind the policy amid widespread outrage.

Few actions during Trump’s time in office have sparked more bipartisan backlash than the family separation policy.

Democrats appear unlikely to pass Trump’s preferred border wall funding without getting major concessions on shielding young immigrants brought to the U.S. illegally as children. Democratic lawmakers in the past have shown a willingness to compromise on border security funding in exchange for legal protections and a pathway to citizenship for at least 1.5 million undocumented immigrants.